src/core/worker_stream.js - master - githubmirror/pdf.js

src/core/worker_stream.js

89 строк2 KB

Jonas Jenwald

Add an abstract `BasePDFStreamRangeReader` class, that all the old `IPDFStreamRangeReader` implementations inherit from

30 янв 2026, 16:15

30 янв 2026, 16:154ca205b

/* Copyright 2019 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {
  BasePDFStream,
  BasePDFStreamRangeReader,
  BasePDFStreamReader,
} from "../shared/base_pdf_stream.js";

class PDFWorkerStream extends BasePDFStream {
  constructor(source) {
    super(source, PDFWorkerStreamReader, PDFWorkerStreamRangeReader);
  }
}

class PDFWorkerStreamReader extends BasePDFStreamReader {
  _reader = null;

  constructor(stream) {
    super(stream);
    const { msgHandler } = stream._source;

    const readableStream = msgHandler.sendWithStream("GetReader");
    this._reader = readableStream.getReader();

    msgHandler.sendWithPromise("ReaderHeadersReady").then(data => {
      this._contentLength = data.contentLength;
      this._isStreamingSupported = data.isStreamingSupported;
      this._isRangeSupported = data.isRangeSupported;

      this._headersCapability.resolve();
    }, this._headersCapability.reject);
  }

  async read() {
    const { value, done } = await this._reader.read();
    if (done) {
      return { value: undefined, done: true };
    }
    // `value` is wrapped into Uint8Array, we need to
    // unwrap it to ArrayBuffer for further processing.
    return { value: value.buffer, done: false };
  }

  cancel(reason) {
    this._reader.cancel(reason);
  }
}

class PDFWorkerStreamRangeReader extends BasePDFStreamRangeReader {
  _reader = null;

  constructor(stream, begin, end) {
    super(stream, begin, end);
    const { msgHandler } = stream._source;

    const readableStream = msgHandler.sendWithStream("GetRangeReader", {
      begin,
      end,
    });
    this._reader = readableStream.getReader();
  }

  async read() {
    const { value, done } = await this._reader.read();
    if (done) {
      return { value: undefined, done: true };
    }
    return { value: value.buffer, done: false };
  }

  cancel(reason) {
    this._reader.cancel(reason);
  }
}

export { PDFWorkerStream };